Accepts an incoming connection returning an array containing the (integer)
file descriptor for the incoming connection, client_socket_fd, and
an Addrinfo,client_addrinfo.

Example

# In one script, start this firstrequire'socket'includeSocket::Constantssocket=Socket.new(AF_INET,SOCK_STREAM,0)sockaddr=Socket.pack_sockaddr_in(2200,'localhost')socket.bind(sockaddr)socket.listen(5)client_fd,client_addrinfo=socket.sysacceptclient_socket=Socket.for_fd(client_fd)puts"The client said, '#{client_socket.readline.chomp}'"client_socket.puts"Hello from script one!"socket.close# In another script, start this secondrequire'socket'includeSocket::Constantssocket=Socket.new(AF_INET,SOCK_STREAM,0)sockaddr=Socket.pack_sockaddr_in(2200,'localhost')socket.connect(sockaddr)socket.puts"Hello from script 2."puts"The server said, '#{socket.readline.chomp}'"socket.close